1. Field of the Invention
This invention is in the field of solar power generation for spacecraft, and in particular relates a photovoltaic blanket of flexible thin film photovoltaics supported in a sail configuration that is stiffened and oriented by the solar wind.
2. Description of the Prior Art
Modern spacecraft are starved for power. For example, a global positioning spacecraft typically requires less power to operate than a standard household hairdryer (about 1.2 kW). Standard solar array designs, which have worked extremely well for decades, are reaching the limit of their capacity to increase the available power to the spacecraft. At the same time, spacecraft are demanding more and more power. For many spacecraft systems, a spacecraft's capability is directly proportional to the amount of power available.
While photovoltaics technology has changed dramatically, standard solar array design has not. Rigid photovoltaics technology has increased in efficiency from less than 10% to, in the near future, greater than 34%. The use of solar concentrators has recently been demonstrated in conjunction with this technology and, possibly, thermal to electric conversion. Probably of most importance, thin film flexible photovoltaics have been developed in workable efficiencies leading to the ability to produce power generation "blankets".
These technical advances place us in a unique position to revisit power generation, storage, and management from a wholly new perspective. The power needs of the future are well understood, but what systems will provide that power are completely unknown. All that is known about these systems is that they will not look anything like current-day systems. There is a tremendous potential to take these revolutionary technical advances in the power area and use them to redefine how spacecraft generate and use power.
The maximum power capacity of current state-of-the-art spacecraft power generation systems is approximately 15 kW. The best performing of these systems typically have a specific energy of 80 W/kg and a cost in the range of $1000/W. The goal of this invention is to develop a new structural concept that, using advances in thin film flexible photovoltaics technology, achieves an order of magnitude improvement in these metrics. The present invention has the potential for generating 100 kW of power, with a specific energy of over 1000 W/kg at a cost of less than $100/W. This is accomplished through a large solar power "sail" that uses the solar wind to provide structure stiffness and pointing.